Full Disclosure mailing list archives

Re: Abusing Windows 7 Recovery Process


From: Chris Arg <grkcharge () gmail com>
Date: Fri, 12 Jul 2013 11:45:57 -0400

Swap out a binary while in recovery...for instance the magnify.exe binary
with cmd.exe. Reboot and at the login screen (if it's still enabled) run
the magnify tool. CMD opens up with SYSTEM privs. Add your local admin user.

Dirty and fast.


On Fri, Jul 12, 2013 at 5:40 AM, Alex <fd () daloo de> wrote:

**

I doubt that you can use the SAM from another computer on yours. The SAM
file is encrypted.

For further reading/information google "bkhive" and/or "samdump2".

I still agree, that the computer is compromised once you get physical
access. If you do it via USB/CD live boot or removing the HDD doesnt matter.



Am 2013-07-10 23:27, schrieb some one:


On Jul 10, 2013 9:16 PM, "some one" <s3cret.squirell () gmail com> wrote:


On Jul 10, 2013 1:51 PM, "Gregory Boddin" <gregory () siwhine net> wrote:

It won't.

The whole point is to have full local access to hard-drives (from a
locked workstation for eg), to modify/read things in it.

The loaded environment IS a live environment. I would say: almost a
copy of the install CD loaded from the hard-drive.

What you can do is : take the SAM, modify somewhere else (not a
windows expert tough), re-inject and gain local access. (which is kind of
useless since local data are already available once the recovery is booted,
unless there's software you would like to run in that workstation once the
password is reset).

Oops, pressed send... Try again...

Hmm, not sure about this...

Haven't tried but lets say recovery console is running as system which can
read the SAM and it lets us copy it off the box to a share or usb or
whatever, if we can get it off i'm guessing we can rip out the hashes for
the users and attempt to crack them, spray them about or whatever...

But changing one so we know the password and then putting it back, doubt
this will work will it, as essentially we are changing the SAM file anyway
aren't we when we create a new legit user through net commands and it
discards this change when we reboot, or are there 2 SAM files? One in live
environment which dissapears and the real one...

Pass, i will try it out again when i get 10mins..:-)


On 9 July 2013 20:39, some one <s3cret.squirell () gmail com> wrote:

My initial thoughts after adding the user and rebooting was that it
was only valid in the recovery console session or something as once i
rebooted it was gone...

Tried it again today in a different place and same deal. Reboot no
new user...

Anyone have this working after reboot?

Once you've inserted your payload with admin-or-better rights, it can
be
anything from a rootkit that GP can't touch to a patched GP subsys
that
doesn't apply AD policies. This isn't really a caveat.


On 2013-07-08 12:39:18 (+0200), Fabien DUCHENE wrote:
There may be an Active Directory domain policy which only allows a
configured set of groups/users to be admin of your workstation.
Keep in mind domain policies are applied at startup and
periodically.

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